Extension 'isaacsim.asset.browser' fails to load due to circular import in requests module

aiden_kim · April 7, 2025, 2:15pm

Isaac Sim Version

[v] 4.5.0
[v] 4.2.0

Operating System

[v] Windows 11

GPU Information

Model: geforce 3060
Driver Version: 560.94

🧵 Topic 1: Extension ‘isaacsim.asset.browser’ fails to load due to circular import in requests module

Detailed Description

I’m using Isaac Sim (build version 4.5.0) on Windows 11.
When launching Isaac Sim, I receive an error indicating that the isaacsim.asset.browser extension fails to load due to a circular import issue in the requests library.

I expected the Asset Browser to load without issue, but instead I encountered a crash with traceback pointing to requests.utils and parse_dict_header.

Steps to Reproduce

Launch Isaac Sim (build 4.5.0)
Wait for all extensions to initialize
Observe errors in the console/log regarding isaacsim.asset.browser

Error Messages

Error: cannot import name 'parse_dict_header' from partially initialized module 'requests.utils' 
(most likely due to a circular import) 
(c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/omni.pip.cloud/pip_prebundle/requests/utils.py)
...
[ext: isaacsim.asset.browser-1.3.4] Failed to startup python extension.

2025-04-07 14:01:11 [7,893ms] [Error] [omni.importer.onshape.client] onshape dependencies not found
2025-04-07 14:01:11 [7,905ms] [Error] [omni.ext.impl.custom_importer] Failed to import python module isaacsim.asset.browser. Error: cannot import name ‘parse_dict_header’ from partially initialized module ‘requests.utils’ (most likely due to a circular import) (c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/omni.pip.cloud/pip_prebundle/requests/utils.py). Traceback:
Traceback (most recent call last):
File “c:\users/kiro/appdata/local/ov/pkg/isaac_sim_450/kit/kernel/py\omni\ext_impl\custom_importer.py”, line 76, in import_module
return importlib.import_module(name)
File "c:\users\kiro\appdata\local\ov\pkg\isaac_sim_450\kit\python\lib\importlib_init.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File “”, line 1050, in _gcd_import
File “”, line 1027, in _find_and_load
File “”, line 1006, in _find_and_load_unlocked
File “”, line 688, in _load_unlocked
File “”, line 883, in exec_module
File “”, line 241, in _call_with_frames_removed
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/isaacsim.asset.browser/isaacsim/asset/browser/init.py”, line 11, in
from .extension import AssetBrowserExtension, get_instance
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/isaacsim.asset.browser/isaacsim/asset/browser/extension.py”, line 18, in
from .window import AssetBrowserWindow
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/isaacsim.asset.browser/isaacsim/asset/browser/window.py”, line 18, in
from .delegate import AssetDetailDelegate
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/isaacsim.asset.browser/isaacsim/asset/browser/delegate.py”, line 20, in
from .context_menu import ContextMenu
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/isaacsim.asset.browser/isaacsim/asset/browser/context_menu.py”, line 16, in
import requests
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/omni.pip.cloud/pip_prebundle/requests/init.py”, line 164, in
from .api import delete, get, head, options, patch, post, put, request
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/omni.pip.cloud/pip_prebundle/requests/api.py”, line 11, in
from . import sessions
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/omni.pip.cloud/pip_prebundle/requests/sessions.py”, line 15, in
from .adapters import HTTPAdapter
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/omni.pip.cloud/pip_prebundle/requests/adapters.py”, line 32, in
from .auth import _basic_auth_str
File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/omni.pip.cloud/pip_prebundle/requests/auth.py”, line 19, in
from .utils import parse_dict_header
ImportError: cannot import name ‘parse_dict_header’ from partially initialized module ‘requests.utils’ (most likely due to a circular import) (c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/omni.pip.cloud/pip_prebundle/requests/utils.py)

2025-04-07 14:01:11 [7,906ms] [Error] [carb.scripting-python.plugin] Exception: Extension python module: ‘isaacsim.asset.browser’ in ‘c:\users\kiro\appdata\local\ov\pkg\isaac_sim_450\exts\isaacsim.asset.browser’ failed to load.

At:
c:\users/kiro/appdata/local/ov/pkg/isaac_sim_450/kit/kernel/py\omni\ext_impl_internal.py(213): startup
c:\users/kiro/appdata/local/ov/pkg/isaac_sim_450/kit/kernel/py\omni\ext_impl_internal.py(328): startup_extension
PythonExtension.cpp::startup()(2):

2025-04-07 14:01:11 [7,906ms] [Error] [omni.ext.plugin] [ext: isaacsim.asset.browser-1.3.4] Failed to startup python extension.

Additional Information

What I’ve Tried

I tried restarting Isaac Sim
Verified the file structure under pip_prebundle/requests/
Looked into replacing the requests module but was unsure if safe under the omni.pip.cloud environment

Related Issues

N/A – haven’t found a matching thread yet

Additional Context

This might be related to the bundled requests library or its improper initialization due to the Isaac Sim import system. The issue blocks the Asset Browser extension from loading properly.

🧵 Topic 2: AttributeError in `get_root_velocities()` when using Humanoid example

Detailed Description

When running the humanoid example in isaacsim.examples.interactive, the simulation crashes after a few seconds due to a missing attribute in the backend during velocity computation.

I expected the simulation to proceed and compute the humanoid’s velocity, but instead, it raises an AttributeError related to a NoneType object.

Steps to Reproduce

Open Isaac Sim (build 4.5.0)
Run the humanoid example script (humanoid_example.py)
Observe crash during physics update steps

Error Messages

AttributeError: 'NoneType' object has no attribute 'count'
...
File "api.py", line 1315, in get_root_velocities
self._root_velocities, self._root_velocities_desc = self._frontend.create_tensor((self.count, 6), float32)

2025-04-07 14:11:03 [599,630ms] [Warning] [isaacsim.core.prims.impl.articulation] Articulation needs to be initialized.
2025-04-07 14:11:03 [599,631ms] [Error] [omni.kit.app._impl] [py stderr]: Traceback (most recent call last):
2025-04-07 14:11:03 [599,631ms] [Error] [omni.kit.app._impl] [py stderr]: File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/isaacsim.examples.interactive/isaacsim/examples/interactive/humanoid/humanoid_example.py”, line 75, in on_physics_step
2025-04-07 14:11:03 [599,631ms] [Error] [omni.kit.app._impl] [py stderr]: self.h1.forward(step_size, self._base_command)
2025-04-07 14:11:03 [599,631ms] [Error] [omni.kit.app._impl] [py stderr]: File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/exts/isaacsim.robot.policy.examples/isaacsim/robot/policy/examples/robots/h1.py”, line 106, in forward
50/exts/isaacsim.core.prims/isaacsim/core/prims/impl/articulation.py", line 2251, in get_linear_velocities
2025-04-07 14:11:03 [599,633ms] [Error] [omni.kit.app._impl] [py stderr]: linear_velocities = self._physics_view.get_root_velocities()
2025-04-07 14:11:03 [599,633ms] [Error] [omni.kit.app._impl] [py stderr]: File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/extsphysics/omni.physics.tensors/omni/physics/tensors/impl/api.py”, line 1315, in get_root_velocities
2025-04-07 14:11:03 [599,634ms] [Error] [omni.kit.app._impl] [py stderr]: self._root_velocities, self._root_velocities_desc = self._frontend.create_tensor((self.count, 6), float32)
2025-04-07 14:11:03 [599,634ms] [Error] [omni.kit.app._impl] [py stderr]: File “c:/users/kiro/appdata/local/ov/pkg/isaac_sim_450/extsphysics/omni.physics.tensors/omni/physics/tensors/impl/api.py”, line 534, in count
2025-04-07 14:11:03 [599,634ms] [Error] [omni.kit.app._impl] [py stderr]: return self._backend.count
2025-04-07 14:11:03 [599,634ms] [Error] [omni.kit.app._impl] [py stderr]: AttributeError: ‘NoneType’ object has no attribute ‘count’

Additional Information

What I’ve Tried

Confirmed this happens on a fresh install of Isaac Sim
Verified physics extension was enabled
Tried delaying physics steps but issue persists

Related Issues

N/A – no existing threads found with similar traceback

Additional Context

It seems like the _backend in omni.physics.tensors.impl.api is not initialized or loaded correctly, possibly due to a race condition or missing dependency during extension startup. I’d appreciate guidance on how to ensure articulation/physics backend is fully initialized before the script proceeds.

VickNV · April 9, 2025, 11:35pm

Let’s use this forum topic to discuss the first issue mentioned.

Please share the full log of launching the Isaac Sim for our investigation.

Topic		Replies	Views
Isaacsim 4.5 crash Isaac Sim isaac-sim-v4-5-0	4	21	April 23, 2025
Failed to import python module omni.isaac.core Isaac Sim isaac-sim-v4-2-0	6	271	January 8, 2025
Isaac sim load error Isaac Sim isaac-sim-v4-2-0	11	174	February 13, 2025
A problem of loading USD files when using isaaclab's tutorials Isaac Sim isaacsim , isaac-lab , isaac-sim-v4-2-0	2	300	December 20, 2024
Warning: Nucleus not configured correctly Isaac Sim	13	2536	April 10, 2022
Error occured during the installation of IsaaC SIM Isaac Sim setup	10	2926	April 5, 2024
Failed to import python module omni.pip.compute and so on Isaac Sim isaac-sim-v4-1-0	0	57	November 26, 2024
Launcher error and Isaac Examples error Isaac Sim	4	522	July 27, 2024
Unable to connect to Isaac-sim from python Isaac Sim cuda , kernel	0	190	May 23, 2024
Isaac sim unable to load after restart [ VkResult: ERROR_OUT_OF_DEVICE_MEMORY] Isaac Sim	7	717	January 22, 2024

Extension 'isaacsim.asset.browser' fails to load due to circular import in requests module

Isaac Sim Version

Operating System

GPU Information

🧵 Topic 1: Extension ‘isaacsim.asset.browser’ fails to load due to circular import in requests module

Detailed Description

Steps to Reproduce

Error Messages

Additional Information

What I’ve Tried

Related Issues

Additional Context

🧵 Topic 2: AttributeError in get_root_velocities() when using Humanoid example

Detailed Description

Steps to Reproduce

Error Messages

Additional Information

What I’ve Tried

Related Issues

Additional Context

Related topics

🧵 Topic 2: AttributeError in `get_root_velocities()` when using Humanoid example